Which preposition to use with orgasm

at Occurrences 1%

When he dedicated himself completely, she counted him to orgasm at the perfect moment; she was pleased; there was no whipping.

of Occurrences 1%

But they had both been struck by their host's impressive obsequiousnessa very orgasm of servility, which Pelletan had hitherto reserved for personages of the blood royal.

Which preposition to use with  orgasm